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Field pussytoes flowerheads are either pistillate (female) or staminate (male), both about 8 mm long, both looking like a compact tuft of white hairs. The very similar plantain-leafed pussytoes (A. plantaginifolia) looks much the same but has basal leaves with three main veins (best viewed from the underside) rather than one.

Antennaria

Antennaria neglecta

field pussytoes [Blooms: Apr-May]

Plantain-leafed pussytoes is a short (6" tall) plant. The basal leaves are 2" wide and 3.5" long, spoon-shaped with long petioles, grayish green, with 3-5 conspicuous main veins; the lower surface is densely covered with appressed hairs and is shiny white. Individual plantain-leafed pussytoe plants bear either male or female flowers exclusively. Flowerheads are short (<1/2" long) and composed exclusively of white disc florets surrounded by a layer of phyllaries; female florets are fluffy white from the profusion of styles (looking a bit like Q-Tips) while male florets show tubular, brownish anthers. Asexual reproduction may produce colonies of exclusively male or female plants. The similar field pussytoes has basal leaves with only a single (rather than 3-5) main veins.

Antennaria

Antennaria plantaginifolia

plaintain-leafed pussytoes [Blooms: Apr-May]

The main stems and some of the lateral branches of dogbane produce panicles of flowers 1-3" across on their tips; the central flowers in the cluster open first. Individual flowers are tiny — 2-3 mm across and 3-5 mm long, bell-shaped, with a fluted edge produced by the 5 white pointed petals. The stamens are shorter than the petals and curve toward the center of the flower, forming a cone over the ovoid stigma.

Apocynum

Apocynum cannabinum

common dogbane [Blooms: Jun-Aug]

Japanese angelica tree may be mistaken for the (native) devil's walking stick, Aralia spinosa. However, the Japanese angelica tree (A. elata) has shorter (although quite substantial) compound leaves, sessile leaflets directly attached to the petiolule, a smaller inflorescence (about 2' tall rather than over 3'), and shorter, less intimidating spines on the trunk. Leaf venation (best viewed from the underside) is the best way to differentiate the two. In devil's walking stick, the pinnate leaf vein tips curve to form a sub-marginal vein parallel to the leaf margin. In the Japanese angelica tree, the leaf veins extend all the way to the margins of the leaf.

Aralia

Aralia elata

Japanese angelica tree [Blooms: Jul/Aug–?]

A small, somewhat shrubby tree up to 25' tall, although half that height is more common in Jackson Park (which is near the northern limit of its range). Devil's walking stick produces a terminal inflorescence of flowers (20+ ft. up). Flowers are small (1/4" long), white and are produced in umbels at the top of the tree. Devil's walking stick has flowers that are either male (bearing stamens) or female (bearing styles). The male flowers of devil's walking stick have prominent stamens and five white, triangular petals; the female flowers (shown here) look like rounded green buds with five stout styles emerging from the distal end.

Aralia

Aralia spinosa

devil's walking stick [Blooms: Aug-Sep]

Bearberry produces small clusters of 2-15 flowers from the tips of the previous year's twigs. Individual flowers are urn- or bell-shaped with a constricted opening ringed by five short lobes, 1/2" long and wide; they have a five-lobed flattened calyx, a white or pink corolla, 10 stamens, and a single style none of which protrude outside the corolla. The flower pedicels are about 1/4" long, red and have a narrow bract at their base. The fruit is a spherical drupe 1/4-1/2" across, initially whitish green but red at maturity.

Arctostaphylos

Arctostaphylos uva-ursi

bearberry [Blooms: April]

Two thyme-leaved sandwort flowers, with leaves clearly visible on the stem on the left of the image. Easily overlooked as just another chickweed, thyme-leafed sandwort's petals are not deeply notched like chickweeds. The stems are 6-10" tall, erect or sprawling, dark purple, and covered with fine hairs. Tiny (4 mm) white flowers on 1/4" pedicels with backward-pointing hairs; flowers have five pointed, white, oblong petals; five hairy green sepals longer than the petals; ten white stamens with magenta anthers; a green central ovary; and three white styles. An exotic from Europe that prefers disturbed areas with minimal other vegetation.

Arenaria

Arenaria serpyllifolia

thyme-leaved sandwort [Blooms: Apr-Jun]

Flowerheads of pale Indian plantain. These plants can be to 9' tall and commonly reach 6+ feet; the stem is pale green to purple with a whitish cast. The flat-topped apical flowerhead is shaped like an inverted pyramid made up of small (1/8x3/8") tubular, cream-colored flowers with five disc florets surrounded by five bracts.

Arnoglossum

Arnoglossum atriplicifolium

pale Indian-plantain [Blooms: Jun-Aug]

Prairie Indian plantain flowerheads are tubular, 3/16" x 3/8", greenish white to reddish white, with five disc florets surrounded by five bracts with white keels (which distinguishes them from pale Indian plantain flowerheads).

Arnoglossum

Arnoglossum plantagineum

prairie Indian-plantain [Blooms: Jun-Jul]

Red chokeberry is a 6-12" tall shrub with multiple stems. Flowers are white with red tinge on the tips of the 5 petals; each flower is ~1" in diameter.

Aronia

Aronia arbutifolia

red chokeberry [Blooms: Apr-May]

Black chokeberry flowers occur in clusters of 7-12 near the margins of the shrub. Each flower is ~1/2" across with a reddish-green calyx with 5 short triangular lobes, 5 white, spoon-shaped, non-overlapping petals with rounded tips and a narrow base, 16-20 stamens with pink to rose-colored anthers, and 5 pale green styles, fused at their bases. The red glands on the upper leaf midvein and pink to rose-colored stamens are diagnostic of black chokeberry.

Aronia

Aronia melanocarpa

black chokeberry [Blooms: May-?]

Mugwort's Inflorescence consists of leafy spikes covered with inconspicuous flowerheads, initially whitish-green, later yellowish- or purplish-green; the flowerheads are egg-shaped, very small (1/8" across) and bear only disc florets (ray florets absent).

Artemisia

Artemisia vulgaris

mugwort [Blooms: Jul-Oct]

Prairie milkweed produces one and a half to two inch balls of 30-100 greenish-white flowers in the axils of a few of the mid-stem and upper leaves; the flowers are supported on 1/2"-3/4" pedicels. Each flower is about 1/8" across and 1/4" long; the flowers are a variation on the typical (complex) milkweed morphology with 5 sepals, a 5-lobed corolla with 5 petals (often with purple blotches at their tips) that are reflected backwards to cover the top of the pedicel, 5 hoods without horns, and a short central column that rises above the hoods; there is a distinct gap between the bases of the petals and the crown. Seedpods are 4-5" long with a fat base (attached to the pedicel) tapering rapidly to a narrow tip. Prairie milkweed can be confused with whorled milkweed (Asclepias verticillata) — both occur in Jackson Park — but whorled milkweed has even narrower (grass-like) leaves than prairie milkweed, is a shorter plant, and has pure white flower that do bear horns.

Asclepias

Asclepias hirtella

prairie milkweed [Blooms: Jun-Aug]

Whorled milkweed's flowers are white, occurring in small (1-3") clusters that rise from leaf axils. Individual flowers are typical milkweeds (except for their color), 1/4" across; horns are sickle-shaped, petals are white or greenish-white. Once you recognize that this plant IS a milkweed, given its grass-like leaves in whorls, it is impossible to mistake it for any other local species.

Asclepias

Asclepias verticillata

whorled milkweed [Blooms: Jul-Sep]

Canada milkvetch flower stalks are ~6" long, covered by numerous (up to 75) cream-colored, tubular flowers (right side of image). Individual flowers are 1/2-3/4" long, slightly drooping, with five petals making up the tube (like an elongated pea flower) and a short (~1/4") cylindrical calyx of the same color with five thin, green teeth; the tip of the upper petal is reflected upwards. The fruits (left side of image) are short, pea-like legumes packed tightly along the flower spike.

Astragalus

Astragalus canadensis

Canada milkvetch [Blooms: Jun-Aug]

White wild indigo is a striking plant that puts up 3-6' tall spikes of white flowers; the flower spikes alone are up to 2' long. Each flower is ~1" long and across with a elongate, triangular bract at the base of the flower pedicel. A short (1/2"), tubular, bluish-green calyx with four triangular teeth encloses the base of a white typical pea-like flower with a forward-leaning banner (one petal, folded up and back along the midline) and a pair of wings (two petals) that enclose a keel (two petals); the keel encloses ten green stamens with orange anthers and the single style.

Baptisia

Baptisia alba

white wild-indigo [Blooms: May-Aug]

Stems of cream wild indigo terminate in 3-9" long flower spikes that sprawl laterally or arch. Each flower is ~1" long and across with a short (1/2"), tubular, light green to light purple calyx with 4-5 triangular teeth, a creamy-yellow (or very yellow) typical pea-like flower with a vertical banner (one petal) and a pair of wings (two petals) that enclose a keel (two petals); the keel encloses ten stamens and the single style. Flowers are held on ~1" long pedicels; at the base of each pedicel, a lance-shaped, 1/2-1" long bract is sessile on the flower stalk. This is our earliest-blooming wild indigo. Flower color, the profuse hairs, and the bracts at the base of each flower pedicel are sufficient to positively identify cream wild indigo.

Baptisia

Baptisia bracteata

cream wild-indigo [Blooms: May-Jun]

Hairy wood mint flowers consist of (from back to front) a tubular, stubby calyx with five long teeth and margins with very long, soft white hairs; a white or light purple tubular corolla with an unlobed upper lip, hairy on the outer surface; and a three lobed lower lip with scattered purple dots. Two stamens and a pistil with a bifurcated stigma protrude. Upper right — an ant for scale on a hairy wood mint flower.

Blephilia

Blephilia hirsuta

hairy wood mint [Blooms: Jun-Aug]